1. Taxonomy 10/11/16 DEVELOPMENT OF EVOLUTIONARY THOUGHT. Development of Evolutionary Thought. Classification of living things

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1 10/11/16 Development of Evolutionary Thought When we think of evolution, we generally think of Charles Darwin DEVELOPMENT OF EVOLUTIONARY THOUGHT Darwin did not invent the concept of evolution. Three preconditions were necessary for the development of evolutionary thought 1. Taxonomy Classification of living things There are roughly 9 million eukaryotic species on the planet 1

2 10/11/16 Carl Linneaus ( ) Father of Modern Taxonomy Organized all creatures using binomial nomenclature using genus and species Homo sapiens (humans) Canis lupis (wolf/dog) Felis catus (house cat) 2. Uniformitarianism the concept that processes that operate in the present operated in the past Charles Lyell Discoveries of fossils of extinct animals Discoveries of deep layers of the earth Discoveries of evidence of ancient seas The Earth is very very very old! 2

3 10/11/16 House of Ussher Archbishop James Ussher (17th century) Used knowledge of Biblical genealogies, average birthtimes, average ages of parents World was created on the night preceding October 23, 4004 B.C. Indicates that people and the earth are both 6000 years old. The lead up to Darwin Recognition of species diversity (taxonomy) Development of uniformitarianism Mechanism of change (genetic inheritance) 3. Mechanism of Change and the recognition that things could change 3

4 10/11/16 Waaaaaay before Darwin. Ancient Greeks All organisms descended from one central, guiding principle (e.g., God, Zeus, etc.) Essentialism - all organisms have essential characteristics that are unalterable Not a tiger? Great Chain of Being Idea that there is a set order to all life from microbes up to God and that this order is PERFECT and cannot be changed. One of its assumptions is that animals cannot go extinct 4

5 10/11/16 Medieval scholars All living things came into existence in unchanging forms Spontaneous generation living things come from inorganic matter (e.g., frogs come from slime) Jean-Baptiste Lamarck First major theory of evolution Argued that organisms strove for increased complexity and improvement Need + Use = Change 5

6 10/11/16 Lamarckism Soft inheritance Notion that acquired characteristics can be inherited Individuals lose characteristics that they do not need Individuals inherit the characteristics of their parents Examples - giraffes stretching their necks; blacksmiths and their sons have large arms Tree of Life Video 6

7 Stick Bug Rattle! Things Darwin observed Tremendous amount of species diversity Diversity occurred over space & time More individuals of all species are born than survive Some animals possess traits that help them survive Defining evolution Dictionary change over time Darwin descent with modification 7

8 o x x x o x x x o x o 1. Source of Variation 2. Selective Pressure 3. Differential Survival o o x o o o o o 4. Transmission to the next generation Evolution through natural selection Organisms will be born with diverse characteristics Organisms with a biological advantage over their peers will be more successful They will survive longer (long enough to reproduce). We say that they have higher fitness Their offspring will inherit their advantageous characteristics Organisms that can produce more viable offspring will thrive Caveats For evolution to act through natural selection, there MUST be an advantage to a trait (or a strong disadvantage). 8

9 Evolution has nothing to say about the origin of life Caveats Traits that are advantages in one place may be disadvantages is other places (this creates diversity) Caveat s Traits must be genetic (not acquired). 9

10 Caveats The longer it takes to reproduce, the longer it takes for evolution to work There is no difference between microevolution and macroevolution Caveats Survival of the fittest does not always mean survival of the smartest, or the strongest, or the fastest 10

11 Lamarck V. Darwin Lamarck - Giraffes NEED to be taller to reach leaves so they will become taller over time by stretching their necks Darwin - Because there is a clear advantage in being taller, those giraffes who were already tall were more likely to reproduce 1. Source of variation 2. Selective Pressure 11

12 2. Selective Pressure 3. Differential Survival Peppered Moths Before industrialization (ca 1690) After industrialization (ca 1790) White Moths 99% 10% Black Moths 1% 90% We cannot always know which traits are good or bad Sexual Selection A specific form of natural selection In sexual selection, females chose males with particular qualities ( the struggle between the males of one species over the females ) 12

13 Intrasexual - males compete over females Intersexual - males must impress females 13

14 Intersexual competition in human groups Evolutionarily Stable Strategy A biological strategy which, if adopted by a population in a given environment, cannot be invaded by any alternative strategy that is initially rare. In other words a biological strategy that is so successful that it is extremely common in many species 14

15 The ability to provide resources is a powerful selective advantage in all organisms Evolution Requires Source of variation Selective force Differential survival Transmission to the next generation But couldn't all this variation be fixed? 15

16 10/11/16 Fossil Record Literally - things dug up from the ground At first, people thought that fossils had two origins: they grew in the ground - like crystals they fell from the sky What do these look like? Trilobite - ca 300,000,000 years ago 16

17 Fossils are Stone Dinosaur bones, trilobites, petrified wood and hominid skeletons are all ROCK This can happen in several ways Fossils may just be molds of the organic material made from mud that hardens into rock Organisms may be buried and the organic compounds are replaced with silica Benefits of Fossils They confirm a proposition of evolution that states that less-complicated life forms should exist before more-complicated life forms Benefits of Fossils They show that some animals went extinct in the past 17

18 Coelacanth They show that some animals changed very little Archaeopteryx And they show that some animals changed...or evolved Intermediate forms If evolution occurs, then there should be missing links Examples: Whales with hind limbs Pythons have pelvises Humans with five toes 18

19 Intermediate human forms Australopithecus afarensis - 3,900,000 years old Homo habilis 2,300,000-1,500,000 years ago Homo ergaster 1,900, ,000 years ago 19

20 Homo neanderthalensis 600,000-30,000 years ago Neanderthal vs. Human 19 TH CENTURY AMERICAN EDUCATION Between 1865 and 1920 American public schools taught evolution as part of standard high school biology curriculum Reconciliation Most Christian organizations accepted evolution as consistent with religious beliefs 20

21 William Jennings Bryan -Presidential Candidate -Opposed evolution because of his distaste for the concept of Social Darwinism THE SCOPES MONKEY TRIAL SCOPES MONKEY TRIAL 21

22 Scopes ended up owing $100 (about $1300 in today s money) FALLOUT FROM THE TRIAL In the 1960s, Christian groups created the concept of Creation Science in order to oppose evolution and demonstrate that the Bible is inerrant and scientifically accurate GENESIS AS A SCIENTIFIC ACCOUNT 22

23 PROBLEMS WITH CS AS SCIENCE Does not produce testable hypotheses Posits that God must be the operator of all processes that are not CURRENTLY understood Fundamentally endorses one religious viewpoint INTELLIGENT DESIGN Movement started in the 1980s by Phillip Johnson Looking at the world through a naturalistic lens is ignoring important sources of data Darwin on Trial Basic premise: life is too complicated to have evolved through random processes. IS INTELLIGENT DESIGN A RELIGION? One of the important legal components of ID is that it does not endorse one religion or promote creation by a deity Practically speaking, all ID proponents are Christian Ancient aliens? 23

24 Teach the Controversy Intelligent Design proponents suggest that educators should teach both evolution and intelligent design and let students choose which theory they prefer. But there is no controversy in the science community 24